Replace Swagger ApiDocs with HealthCheck

[diesalbla]

Description

The backend server contains some files for the style of a Swagger documentation which is not to be completed. Its only use is as a sort of publicly accessible health check for the API.

1. Remove the apiDocs route from the API and the Swagger documentation from the repository.
2. Add a publicly accessible /healthCheck endpoint that replies with a success 200 OK response.